6. The incidence of Down syndrome will be very high(somewhat less than 50%) among the offspring of aparent with Down syndrome. Diagram meiosis in theDown syndrome parent to explain why progeny havesuch a high risk for chromosome 21 aneuploidy.Explain in addition why the incidence of Down syndrome among these children might be less than 50%.

6. The incidence of Down syndrome will be very high(somewhat less than 50%) among the offspring of aparent with Down syndrome. Diagram meiosis in theDown syndrome parent to explain why progeny havesuch a high risk for chromosome 21 aneuploidy.Explain in addition why the incidence of Down syndrome among these children might be less than 50%.

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Description: 6. The incidence of Down syndrome will be very high(somewhat less than 50%) among the offspring of aparent with Down syndrome. Diagram meiosis in theDown syndrome parent to explain why progeny havesuch a high risk for chromosome 21 aneuploidy.Explain

Biology: The Unity and Diversity of Life (MindTap Course List)

14th Edition

ISBN:9781305073951

Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr

Publisher:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr

Chapter14: Chromosomes And Human Inheritance

Section: Chapter Questions

Problem 3GP: Human females have two X chromosomes (XX); males have one X and one Y chromosome (XY). a. With...

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Figure 13.6 Which of the following statements about nondisjunction is true? Nondisjunction only results in gametes with n+1 or n-1 chromosomes. Nondisjunction occurring during meiosis II results in 50 percent normal gametes. Nondisjunction during meiosis I results in 50 percent normal gametes. Nondisjunction always results in four different kinds of gametes.
Human females have two X chromosomes (XX); males have one X and one Y chromosome (XY). a. With respect to X-linked alleles, how many different types of gametes can a male produce? b. If a female is homozygous for an X-linked allele, how many types of gametes can she produce with respect to that allele? c. If a female is heterozygous for an X-linked allele, how many types of gametes can she produce with respect to that allele?
11. Refer to the figure showing a cell with two pairs of homologous chromosomes in prophase I of meiosis. Genes A (alleles A and a) and D (alleles D and d) are located on the longer pair of chromosomes, and gene B (alleles B and b) is located on the shorter pair. BOOB centromere DoD dood 2 chromatids = chromosome How many different combinations of A, B and D alleles are possible in the genotypes of the daughter cells produced from this cell? O 16 8. O O O O
3. A nondisjunction occurs in the sex chromosomes of a male mouse. What ratio of sex chromosome genotypes would you expect among the gametes in the two following scenarios. Make sure to includethe gamete’s sex chromosome genotype in your genotypic ratio. (A) The nondisjunction of the sex chromosomes occurs only in Meiosis I? (B) The nondisjunction of the sex chromosomes occurs only in Meiosis II?
15. Using diagrams, illustrate how nondisjunction can result in an aneuploid zygote.
37. Answer each question about this diagram: ZWKOI KEY %3D 13 22 1> This individual's sex is female [Choose ] trisomy 21 karyogram 2n 2> The genetic disorder revealed is triplo X 1n 3> This type of diagram is called a genetic map male polyploidy female 4> The ploidy number of this 46 individual is ancuploidy 5> The term to describe this disorder polyploidy as the incorrect pumber of to search :-
8. Down Syndrome most commonly results from having three copies (trisomy) of chromosome 21 instead of two. Below is a fertilization event that could have given rise to Down Syndrome. Identify samete is abnormal and explain how the abnormal gamete could have been produced from a hondisjunction event in meiosis I and from a nondisjunction event in meiosis i.
17. A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19. If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, and has both number 19 chromosomes with short genes, she will produce which of the following egg types? (LS3-2) * only blue short gene eggs only orange short gene eggs one-half blue short and one-half orange short gene eggs three-fourths blue short and one-fourth orange short gene eggs
1. Down Syndrome (trisomy 21) is caused by an error in meiosis which results in the presence of three chromosome #21s in the individual affected. In what two phases of meiosis could this error occur and, in general, HOW does it occur? 2. You are exploring a new planet when you discover a hexaploid (6n) organism. What is the ploidy of the gametes of wheat after meiosis and cytokinesis (what does 6n become)? 3. If a somatic cell has a diploid number of 4, what would be the result in the final daughter cells after cytokinesis IF in Anaphase, one of the chromosomes did not have a separation of sister chromatids? That is, if the sister chromatids of ONE of the chromosomes stayed together, what would be the chromosome number of each daughter cell? What problems might be caused by this happening?
A. 1. Division of the cell nucleus, results in two daughter nuclei, each have the same number of chromosomes as the parent nucleus. 2. One two identical halves of a duplicated chromosome. 3. Fusion of haploid (n) gametes; results in the formation of a diploid (2)n zygote. 4. The breaking and rejoining of homologous (non sister) chromatids during early meiotic prophase I, resulting in an exchange of genetic material. 5. The diploid (2n) cell that results from the union of haploid (n) gametes in sexual reproduction. 6. The condition of having one set of chromosomes per nucleus. 7. The complex of DNA, proteins and some RNA that makes up eukaryotic chromosomes. 8. Structures in the cell nucleus, composed of chromatin and containing the genes. 9. An X-shaped site in a tetrad marking the location where homologous chromatids previously underwent crossing over. 10. A sex cell; in plants and animals, an egg or sperm. 11. Type of reproduction in which two gametes (usually, but not necessarily,…
1. How many asci contain a parental order of ascospores? 2. How many asci contain ascospores representing crossing over? 3. How many total segregants were analyzed? 4. What is the distance from the spore color gene to the centromere?
. If you were asked to complete the table with the correct answer, which of the following table would you chose? А. CHITERIA MITOSIS MEIOSIS 1. Na. of nuciear dimsion 2. Syriapaia/crossing over ECentromere of suster chromatids atanaphase Preseut separates Fresent M-attached/M-separates Haploid S. Na of chromosomes per daughter cell 6 Function Diplaid Growth. Rapair Growth. Repair and Reproduction B. CRITERIA MITOSIS MEIOSIS TNo, af nuclear darinion Synapsin/croing over 3. Centromere af sister chromatids at anaphase Absetit sepiarates Fresent -attached FNo. of daughter cells 5. No. of chromosomes per daughter cell 6 Function Diploid Haploid Growth, Eapair Growth, Repair and Reproduction C. CRITERIA MITOSIS MEIOSIS 1. No. of muclear division 2. Synapsis/crossing over 3. Centromereof sister chromatids at anaphane 4 Na, af daughter cells 5. No. of chromosoetes per daughter cell 6 Punction Absent Present separates MI-attached/Mli-separates Haploid Diploid Gruwth, Repair Reproduction D.…